Boiler construction



Feb. 15, 1966 J. G. MUELLER BOILER CONSTRUCTION Filed Aug. 9, 1965United States Patent C) 3,234,899 BOILER CONSTRUCTION Johannes G.Mueller, Michigan City, Ind., assigner to Weil-McLain Company, Inc.,Michigan City, Ind., a corporation of Indiana Filed Aug. 9, 1963, Ser.No. 301,070 5 Claims. (Cl. 110-173) The present invention relates toheating equipment and, more specically, to the construction yof #boilersand related apparatus.

In general, this invention is concerned with improvements in theconstruction of boilers and related apparatus which provides forpressure relief in the face of excessive internal boiler pressure andallows visual inspection of the boiler interior. These improvements areapplicable to small boilers, for example, domestic size boilers as wellas large 'boilers utilized in heating plants for large buildings.

A primary object is to provide improved pressure relief means forboilers. More specifically, it is an object to provide improved pressurerelief means for normally maintaining a gas-tight seal and for openingto relieve pressure in the face of gas puffs or excessive internalpressure in the rebox. A related object is to provide such means whichallows for visual inspection of the boiler interior.

Another general object is to provide an improved boiler constructionwherein the construction facilitates efciency of operation and safety ofoperation.

Other objects and advantages of the invention will become apparent asthe following description proceeds, taken in conjunction with thedrawings, in which:

FIG. la is a front, elevational View of progressive pressure reliefapparatus for utilization in conjunction with a boiler and relatedapparatus,

FIG. 1b is an enlarged cross-sectional view Itaken along line 1--1 inFIG. la; and

FIGS. 2a, 2b and 2c are illustrative of three possible positions for thepressure relief apparatus illustrated in FIG. 1.

While the invention has been described in connection with a certainillustrative embodiment, it is to be understood that the invention isnot to be limited to the disclosed em-bodiment but, on the contrary, theinvention is intended to cover the various modifications and equivalentarrangements included within the spirit and scope of the appendedclaims.

For the purpose of describing a preferred environment for the presentinvention, it is described in connection with a sectional type boiler,that is, a boiler unit made up of a plurality of individual rectangularshaped sections which are fastened together by mechanical devices andwhich define a iirebox located centrally in the lower portion thereof.For details of an illustrative boiler to which the present invention maybe advantageously utilized with, reference is made to my copendingapplication, Ser. No. 300,898, led Aug. `S, 1963.

In accordance with the present invention, pressure relief means isprovided for opening when the internal boiler pressure exceeds a desiredlimit -to allow for the escape of gas puffs or the like. Referring toFIGS. 1a and 1b, pressure relief apparatus 40 is illustrated which isconstructed in accordance with this feature of the present invention.The pressure relief apparatus is mounted `at the rear of the boiler,adjacent a rectangular pressure relief opening 41 (FIGS. 1a and 1b)provided adjacent the boiler iirebox.

The pressure relief apparatus 40 includes a main pressure relief plate42 having a circular opening or port 42a 3,234,899 Patented Feb. 15,1966 ICC disposed in the center thereof. In keeping with this feature ofthe present invention, the relief plate 42 is resiliently secured ltothe last boiler section so that the relief plate is normally maintainedin engagement therewith and so that the relief plate is free to bedriven away from the last boiler section when excessive internalpressure in the rebox is developed. In the exemplary embodiment, themain relief plate 42 is secured to the boiler by means of spring-loadedbolts 44 which extend through grooves or slots 45 in the relief plateand are threaded into the last boiler section. As may be seen, eachspringloaded bolt 44 includes a spring 44a disposed between Aa headportion 4417 of the bol-t and a collar washer 44C which engages theouter surface'of the'relief plate 42. Two such spring loaded washers areprovided at both the top `and bottom of the relief plate 42 in theexemplary embodiment (see FIG. la). Alternatively, a three pointsuspension may be utilized wherein a single spring-loaded bolt will beprovided at either the top or the `bottom of the relief plate at thecenter thereof in lieu of two spring-v loaded bolts, such a third boltbeing illustrated in dotted lines at the top of the relief plate 42 inFIG. la.

For the purpose of maintaining a positive seal, a sealing medium such asasbestos rope 46 may be disposed between the relief plate 42 and thelast boiler section, the asbestos rope being compressed therebetween.

In view of the foregoing, it will be apparent that, when excessiveinternal pressure in the iirebox is developed, a corresponding forcewill be applied to the top and/or bottom of the relief plate 42 so thatthe relief plate will be driven away from the last boiler section, tothe left in FIG. 1b whereby gas mayescape from the boiler interiorthrough the opening 41. As the relief plate 42 is driven to the left,the springs 44a of the associated spring-loaded bolts 44 will becompressed between the collars 44C and the head portions 44b thereof.Subsequently, when the pressure is relieved, the springs 44a will drive`the relief plate 42 back into sealing engagement with the last boilersection, to the `right in FIG. la.

A secondary pressure relief plate 48 is provided for sealing thecircular opening 42a in the main relief plate 42. Likewise, in keepingwith this feature of the invention, the secondary relief plate 48 isresiliently secured to the main relief plate I42 so that it is free tobe driven 4away from the main relief plate. As illustrated, it issecured thereto by means of a spring-loaded bolt 49. The spring-loadedfbol-t 49 is substantially identical to the spring-loaded bolts 44 andincludes a spring 49a disposed between the outer surface of =the reliefplate l48 and the head portion 4912 of the bolt. The bolt 49 extendsthrough an opening in the relief plate 48 and is threaded into asupporting rib member 50 extending across the circular opening 42a inthe main relief plate 42, 'the ends of the rib member engaging the innersur-face of the relief plate 42. Thus, the relief plate i48 is driveninto sealing engagement with the main relief plate 42 by the spring 49which urges the plate toward the right as viewed in FIG. lb. It is Itobe understood that a desired sealing medium is provided for preventingthe escape of gas between the bol-t 49 and the opening 48a, i.e., formaintaining the boiler interior positively sealed, though lthe detailsof such sealing medium will not be set forth.

In view -of the foregoing, it will be apparent that, when excessiveinternal pressure in the rebox is developed, a corresponding force willbe applied to the inner surface of the relief plate `48 so that therelief plate will be driven away from the relief plate 42 (to the leftas viewed in lFIG. 1b) whereby gas may escape from the boiler interior.through the opening 42a -in the relief plate 42. As the relief plate 48is driven to the left, the spring 49u will be compressed between therelief plate 4S and the head portion 49h. Subsequently, when thepressure surbsides, the spring 49a will drive the relief plate 48 `backinto sealing engagement with the relief plate 4Z, to the right in FIG.v1b.

lt follows that the springs 49a and 44a may be selected such that therelief plate 48 will be driven to the left in FIG. 1b in the face ofless pressure than the relief plate 42. For example, the spring 49a maybe selected such that the relief plate 48 will be driven to the leftwhen. the internal pressure in the iirebox exceeds 1/2 H2O. Conversely,the springs 44a may be selected such that the main relief plate 4Z willbe driven to the left when the internal pressure in the irebox exceeds avalue of approxi mately l H2O. Accordingly, the secondary relief plate48 will allow for pressure relief in the face of minor pressureincreases such as created by gas puffs or the like, whereas the mainrelief plate 42 will allow for pressure relief in the face of large,excessive boiler pressures.

For the purpose of providing a better understanding of the variouspressure relief positions with the illustrated arrangement, reference ismade to FIGS. .2a-lc. In FIG. 2a, the pressure relief apparatus 40 isillustrated in a rst position wherein the secondary relief plate 48 isopened, whereas the main relief plate 42 is still closed. Such would bethe case when a small excessive internal pres sure is created.Subsequently, if the internal pressure increases even more, the mainrelief plate 42 may be partially opened and the secondary relief plate4S fully opened such as illustrated in FIG. 2b wherein the main reliefplate is in a tilted position, this representing a second reliefapparatus position. Such would be the case when a moderately excessivepressure is created within the boiler. Finally, should the pressurewithin the boiler become unusually excessive, both the secondary relieflate 48 and the main relief plate 42 will be fully opened as` shown inFIG..2C, so that maximum relief is provided, this representing a thirdpressure relief position.

Turning again to FIGS. la and lb, it may seem that a circulartranslucent observation port 52, constructed of glass or the like, isprovided in the relief plate 48 so that the interior of the boiler maybe viewed during operation thereof. Additionally, as may be seen, thepressure relief plate is backed with insulation 53 having an opening orport 53a therein which with the relief plate in the position shown inFIG. 1b is in alinement with the glass plate 52 to allow for viewing ofthe interior. Since the opening 53a is provided only in the upperportion of the insulation, it will be apparent that the relief plate 4Smay be rotated to a position wherein the interior of the boiler is nolonger observable through the glass plate 52, the latter being out ofalinement with the opening 53a in the insulation. Such rotation ispossible since, as previously mentioned, the relief plate 4S isresiliently mounted on the relief plate 42.

In view of the foregoing, it will be seen the invention provides aboiler construction which provides for pressure relief and provides forviewing the interior of the boiler during operation thereof.

I claim as my invention:

1. In apparatus for sealing a pressure relief opening to a boiler or thelike, the combination which comprises, a pressure relief plate adaptedto be mounted adjacent the pressure relief opening and having anobservation port, and spring-loaded means for rotatably alining therelief plate observation port with the relief opening and forresiliently seating the relief plate in sealing relationship with theboiler so that the relief opening is sealed and .the relief plate isfree to be driven away from the boiler when the Ainternal rebox pressureexceeds a desired level and when said central port and said observationport are out of alinement, the observation port allowing for visualinspection of the boiler interior when said ccntrol port and saidobservation port are in alinement.

2. In pressure relief apparatus for a boiler or the like, thecombination which comprises, a main pressure relief plate adapted to bemounted adjacent a pressure relief opening and having a central portprovided therein, a secondary pressure relief plate adapted to bemounted adjacent the central port, spring-loaded means for alining themain relief plate with the relief opening and for resiliently lockingthe main relief plate in sealing relationship with the boiler so thatthe relief opening is sealed and the main relief plate is free to bedriven away from the boiler when the internal fire box pressure exceedsa desired level, and spring-loaded means for alining the secondaryrelief plate with the central port and for resiliently locking thesecondary relief plate to the main relief plate so that the central portis sealed and the secondary relief plate is free to be driven away fromthe main relief plate when the internal firebox pressure exceeds adesired level, the spring-loaded means having selected sealing forceswhich are so related that one of the relief plates is affected at alower internal pressure: level than the other.

3. In pressure relief apparatus for a boiler or the like,.

the combination which comprises, a main pressure relief: plate adaptedto be mounted adjacent a pressure relief, opening and having a centralport provided therein, a sec-- ondary pressure relief plate adapted tobe mounted ad jacent the central port, heat resistant exible ropedisposed: around the inner surface of the main relief plate at theyperiphery thereof, means including a spring-loaded bolt for alining thesecondary relief plate with the central port and for resiliently seatingthe relief plate to the main relief plate so that the secondary reliefplate is free to be driven away from the main relief plate when theinternal irebox pressure exceeds a `desired level, and means includingspring-loaded bolts disposed in selected spaced positions around theperiphery of the main relief plate for alining the main relief platewith the relief opening and for resiliently seating the relief plate tothe boiler so that the rope is compressed therebetween whereby therelief opening is sealed and so that the main relief plate is free to bedriven away from the boiler when the internal tirebox pressure exceeds adesired level, the spring-loaded boits having sealing forces such thatthe secondary reiief plate is affected by a lower pressure than the mainrelief plate.

d. In pressure relief apparatus for a boiler or the like, thecombination which comprises, a main pressure relief plate adapted to bemounted adjacent a pressure relief opening for sealing thereof andhaving a central port provided therein, means including a plurality ofspring-y loaded bolts for seating the main relief plate to the boiler,each bolt including a head portion and a spring which is disposedbetween the head portion and the main relief plate so that the reliefplate is thereby driven into resilient sealing relationship with theboiler and is free to be driven away from the boiler when the internalrebox pressure: exceeds a desired level, a secondary pressure reliefplatel adapted to be mounted adjacent the central port for seal-- ingthereof, and means including a spring-loaded bolt for: seating thesecondary relief plate on the main relief plate,.

the spring-loaded bolt including a head portion and a.

spring which is disposed between the head portion and' the secondaryrelief plate so that the secondary relief plate is thereby driven intoresilient sealing relationship with the main relief plate and is free tobe driven away from the main relief plate when the internal reboxpressure exceeds a desired level.

5. In pressure relief apparatus for a boiler or the like, thecombination which comprises, a main pressure relief plate adapted to bemounted adjacent a pressure relief opening to the boiler and having acentral port formed therein, a secondary relief plate adapted to bemounted adjacent the central port and having a translucent observationport formed therein, means including spring-loaded bolts for alining themain relief plate with the relief open ing and for resiliently seatingthe main relief plate in sealing relationship with the boiler so thatthe relief opening is sealed and the relief plate is free to be drivenaway from the boiler when the internal firebox pressure exceeds adesired level, and means including a spring-loaded bolt for rotatablyalining the secondary relief plate observation port with the centralport and for resiliently seating the relief plate to the main reliefplate so that the secondary relief plate is free to be driven away fromthe main relief plate when the internal rebox pressure exceeds a desiredlevel and when said central port and said observation port are out ofalinement, the observation port allowing for visual inspection of theboiler interior When said central port and said observation port are inalinement.

References Cited by the Examiner UNITED STATES PATENTS Longard 122-225Werner 110-173 X Neumann 110-173 X Sauvage 110-173 X Mahon 126-200Macchi 110-173 Ayers 110-173 Cleaver et al. 122-75 Patrick 110-173Duggan et al 55-200 FREDERICK L. MATTESON, JR., Primary Examiner. JAMESW. WESTHAVER, Examiner.

1. IN APPARATUS FOR SEALING A PRESSURE RELIEF OPENING TO A BOILER OR THELIKE, THE COMBINATION WHICH COMPRISES A PRESSURE RELIEF PLATE ADAPTED TOBE MOUNTED ADJACENT THE PRESSURE RELIEF OPENIONG AND HAVING ANOBSERVATION PORT, AND SPRING-LOADED MEANS FOR ROTATABLY ALINING THERELIEF PLATE OBSERVATION PORT WITH THE RELIEF OPENING AND FORRESILIENTLY SEATING THE RELIEF PLATE IS SEALING RELATIONSHIP WITH THEBOILER SO THAT THE RELIEF OPENING IS SEALED AND THE RELIEF PLATE IS FREETO BE DRIVEN AWAY FROM THE BOILER WHEN THE INTERNAL FIREBOX PRESSUREEXCEEDS A DESIRED LEVEL AND WHEN SAID CENTRAL PORT AND SAID OBSERVATIONPORT ARE OUT OF ALINEMENT, THE OBSERVATION PORT ALLOWING FOR VISUALINSPECTION OF THE BOILER INTERIOR WHEN SAID CENTRAL PORT AND SAIDOBSERVATION PORT ARE IN ALINEMENT.